Elucidations of energy, duration and cost of domestic cooking of African yam bean seed

Abstract

Long duration of cooking limits domestic consumption of African Yam bean (AYB) seed, an edible legume.  Reduction in energy demand during domestic cooking of AYB seed was the focus of the work.  The seed was soaked in ambient temperature, and also cooked to determine hydration curve.  AYB seeds (153 g) were cooked using kerosene, electric, Liquefied Petroleum Gas (LPG), and charcoal stoves.  Normal, control, open and pressure cooking were done.  Cooking duration, energy consumed, water evaporation and cost were determined using standard procedures.  Moisture content of the seed increased with soaking time while rate of water absorption decreased.  Temperature significantly influenced both moisture content and water absorption rate.  Energy consumption varied with methods of cooking regardless of energy source.  Pre-soaked control pressure cooked method consumed least energy using kerosene (4,849.7 kJ), electric (3,085 kJ), and LPG (2,673 kJ) stoves.  Pre-soaked pressure control electric cooking method was the cheapest energy source (US $0.071), although not significantly different from pre-soaked pressure control LPG (US $0.075).  While un-soaked open normal kerosene method was most expensive (US $0.342).  Shortest cooking time of 55 minutes was recorded in pre-soaked pressure normal electric stove while un-soaked open control LPG method duration of 170 minutes was the longest.  Opening and closing of pot majorly determined the energy loss due to evaporation.  Generally, controlled energy input, cooking at high pressure, and soaking of AYB seeds before cooking independently reduced the energy required for cooking.

Keywords: African yam bean, seed, hydration behaviour, cooking method, energy source